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FNUS38 KWNS 182119

PFWF38



DAY 3-8 FIRE WEATHER OUTLOOK AREAL OUTLINE

NWS STORM PREDICTION CENTER NORMAN OK

0317 PM CST THU FEB 18 2021



VALID TIME 201200Z - 261200Z



FIRE WEATHER OUTLOOK POINTS DAY 3-8



... CRITICAL FIRE WEATHER AREA ...



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FNUS28 KWNS 182119

FWDD38



Day 3-8 Fire Weather Outlook  

NWS Storm Prediction Center Norman OK

0317 PM CST Thu Feb 18 2021



Valid 201200Z - 261200Z



The broad trough that remains over the central CONUS is forecast to

begin exiting off the east coast by the beginning of the extended

period. To the west, modest upper-level ridging over the

inter-mountain west will proceed a shortwave trough moving onto the

California coast early Saturday. This feature is expected to

translate across the West over the weekend, bringing windy

conditions to the Southwest. In general, fuels will be a mitigating

factor for most regions across the U.S. after several days of

below-normal cold and widespread precipitation. A warming trend over

the next several days may allow fuels to dry across the Southwest

ahead of additional disturbances mid-week.



...D3/Saturday and D6/Tuesday to D7/Wednesday - Southwest...

Modest surface pressure falls along the NM/CO border are expected

through the day Saturday ahead of an approaching shortwave trough.

Winds will likely increase to 15-25 mph across AZ and NM in

response, and downslope effects may allow for areas of reduced

relative humidity near/below 20%. However, fuel analyses currently

show seasonal ERC values and fuel moisture values generally above

10%. Although little to no precipitation is expected through

Saturday, it is unclear whether or not fuels will sufficiently dry 

to support a substantial fire weather threat. 



Long-range deterministic and ensemble guidance show the potential

for additional fire weather concerns by the middle of the upcoming

week. Increasing zonal flow over the central/southern Rockies ahead

of a shortwave trough may support persistent lee troughing and

westerly downslope flow across eastern CO/NM. Fuel status by the

D6/D7 time frame is uncertain, but little precipitation is expected

through this period and may allow for grassy fuels to cure and

support a fire weather threat. 



...D3/Saturday to D4/Sunday - Southern California...

Another offshore wind event remains possible for southern CA over

the weekend as surface high pressure builds over the northern Great

Basin. Recent guidance has trended slightly faster with the onset of

the event with some solutions showing northerly offshore winds

beginning for portions of Santa Barbara county by D3/Saturday

evening. Most solutions are calling for a -7 to -9 mb LAX-TPH

pressure gradient, similar to the observed gradient during

today/Thursday's offshore wind event. As such, wind gusts upwards of

30-40 mph appear reasonable for wind-prone locations along the

southern CA coast. Relative humidity values may be the lowest on

D4/Sunday afternoon, falling into the teens for the coastal hills.

Fuels along the coast have begun to dry per recent ERC analyses, but

the degree of fuel readiness and spatial extent of the fire weather

concern remains uncertain.



..Moore.. 02/18/2021



...Please see www.spc.noaa.gov/fire for graphic product...



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